The invention relates to collimators, and more particularly relates to fucussing collimators for use in single photon emission computerized tomography, or SPECT. In its most particular sense, the invention relates to focussing collimators for use in SPECT examinations of distal body parts such as the head.
As a gamma camera is brought closer to a body organ to be imaged, the quality of the image generally improves. This occurs because the resolution of the system improves as the distance to the collimator decreases.
A conventional collimator used in transaxial rotational camera SPECT is parallel to the axis of rotation. In cranial examinations, this arrangement produces a relatively wide gap between the top of the brain and the sensitive crystal surface, and a corresponding reduction in resolution there.
One object of the invention is to provide a collimator which can reduce, on an overall basis, the gap between the sensitive crystal surface and a distal body part such as a patient's head, with consequential improvement in system resolution.
Another object is to generally improve the sensitivity of cameras used for SPECT examinations and to reduce data acquisition time.
A further object is to improve on existing cranial scanning technique and apparatus.
Yet another object is to generally improve on the prior art.